1. Field of Invention
The present invention relates to a technique for evaluating stereo image quality, and more particularly to a method for objectively evaluating stereo image quality based on binocular fusion and binocular suppression.
2. Description of Related Arts
With the progressive development of three-dimensional display technologies, stereo image technologies are widely utilized in various fields. However, how to establish an effective method for evaluating stereo image quality which is in accordance with visual perception of human beings has been a hot topic of research in fields of stereo image processing or compression.
From the point of methodology, the stereo image quality evaluation can be classified as two methods, which are respectively a subjective quality-evaluation method and an objective quality-evaluation method. The subjective quality-evaluation method means processing visual perception and quality evaluation on stereo images by a large number of testers. Since the subjective quality-evaluation method is very inconvenient to operate and consumes plenty of time, manpower and physical resources, the ultimate object of stereo image quality assessment is to establish an objective quality-evaluation model which is capable of automatically evaluating and has an evaluation result in accordance with the subjective quality-evaluation result.
The objective quality-evaluation method predicts visual quality of the stereo image to be tested by modeling distortion information, and thus plays an important role in fields of video processing. For example, the objective quality-evaluation method is utilized for monitoring and regulating image quality, optimizing algorithm and parameter settings, evaluating performances of system or algorithm and etc. Currently, multiple methods for objectively evaluating quality of a stereo image are presented by researchers. A first representative method thereof is to evaluate left-view and right-view images of the stereo image respectively by a 2D quality evaluation method directly, and an average value of the results obtained serves as a predictive value for the quality of the stereo image. A second representative method thereof is to separate the stereo-image quality evaluation into two parts: 2D distortion evaluation and stereo distortion evaluation. In the first method, the stereo image is regarded as an assembly of left-view image and right-view image which are independently existed completely without any consideration for the special characteristics of the stereo image. Based on the first method, the second method evaluates the specific quality distortion of the stereo image simply by depth or disparity information thereof. It is obvious that both of the two methods mentioned above are extension or improvement of the 2D-image quality evaluation method. Compared with a 2D image, the stereo image not simply has an extra channel added, and quality evaluation thereof has several difficult problems as following:                (1) the problem of evaluating the specific distortion type of the stereo image, such as crosstalk, cardboard and keystone;        (2) the problem of presenting depth perception information of the stereo image and evaluating distortion thereof;        (3) the problem of interaction between the left-view and the right-view of a stereo image.        
Currently, the problems mentioned above have not been solved yet, which leads to inconsistency between the visual quality of the stereo image and evaluating results of the conventional objective quality-evaluation model.